Sony Trinitron S-Video/Composite Mod (RF-Only TV) SOLVED

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jeffez
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Sony Trinitron S-Video/Composite Mod (RF-Only TV) SOLVED

Post by jeffez »

Edit:
TLDR see here for solution:
viewtopic.php?f=6&t=65583&start=66

Hi Guys
Looking to see if there are any crt gurus on here who can help me out.
I have been working on getting s-video working on an old trinitron crt. The jungle chip doesn't look to have any rgb inputs but it does have Luma and Chroma.
The one i am modding is the smaller one pictured below which only came with an rf antenna input.

Image

Model number : KV1414AS
Jungle : CXA-1213S
GP-1A chassis

No service manual could be found for this exact model but this one is basically the same
https://elektrotanya.com/sony_kv-2170m3 ... nload.html
This tv has the same jungle with an s-video input
https://elektrotanya.com/sony_gp-1a_kv- ... nload.html
Jungle datasheet
https://www.alldatasheet.com/datasheet- ... 213AS.html

I have tried the configuration that the s-video tv uses in the second link above but only got a black screen with the green channel number showing.
The only setup where i got any success was inserting the Luma and Chroma directly from the s-video port into the jungle which results in the image below. I was told this could be sync related but not entirely for sure. It's trying to show the title screen of snes dk2.

Image

Can anyone offer any advice on what they might try? Happy to provide more info/schematics etc. Just trying to not let this initial post get too long.
Thanks.
Last edited by jeffez on Wed Apr 13, 2022 3:45 am, edited 4 times in total.
MarkOZLAD
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Re: Sony Trinitron S-Video Mod

Post by MarkOZLAD »

Did you run 75 ohm termination in your luma?
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jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

No, could this be the issue? I basically i have replaced the Y C lines and kept with the same configuration the tv uses. Here is a diagram of what i have setup.
Image
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Re: Sony Trinitron S-Video Mod

Post by MarkOZLAD »

Image

If I were going straight to the jungle I’d go luma 75R to ground, capacitor, jungle.
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jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

Thanks you. So i tried that for luma with a 100uF in series but got a black screen. I can see in your diagram there is also a 75R to ground for chroma so i tried that and now i have colour showing in the scrambled output as seen in the my pic above, so we are getting closer. I keep thinking i need to also connect luma somewhere for sync but i am not sure where. The jungle doesn't appear to have a sync input pin. It does have sync out and hsync in and vsync in though.
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

I got it working. As i suspected it wasn't using the sync signal on the luma pin. I fed luma into the video signal coming from the tuner block and got a picture. I also switched to a 0.1uf on chroma. The difference is huge from how it looked before. I can post more details if anyone is interested.
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Re: Sony Trinitron S-Video Mod

Post by MarkOZLAD »

jeffez wrote:I got it working. As i suspected it wasn't using the sync signal on the luma pin. I fed luma into the video signal coming from the tuner block and got a picture. I also switched to a 0.1uf on chroma. The difference is huge from how it looked before. I can post more details if anyone is interested.
Nice.

Would love to see more details/some photos.
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buttersoft
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Re: Sony Trinitron S-Video Mod

Post by buttersoft »

jeffez wrote:I got it working. As i suspected it wasn't using the sync signal on the luma pin. I fed luma into the video signal coming from the tuner block and got a picture. I also switched to a 0.1uf on chroma. The difference is huge from how it looked before. I can post more details if anyone is interested.
I did say to try that in the other thread, surely?

It's easy to give armchair advice, but you're the man on the ground, so nice job on this one. Please post up (in both places) with the circuit you got working :)
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Bratwurst
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Re: Sony Trinitron S-Video Mod

Post by Bratwurst »

Yeah this is a solid thread, please post as many pictures/further elaboration as you'd like.

I have a Zenith 13" I want to see about shooting S-video into since it's RF-only, but schematics are scarce and Zenith liked to march to the beat of their own drum.
jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

buttersoft wrote:
jeffez wrote:I got it working. As i suspected it wasn't using the sync signal on the luma pin. I fed luma into the video signal coming from the tuner block and got a picture. I also switched to a 0.1uf on chroma. The difference is huge from how it looked before. I can post more details if anyone is interested.
I did say to try that in the other thread, surely?

It's easy to give armchair advice, but you're the man on the ground, so nice job on this one. Please post up (in both places) with the circuit you got working :)
You did yes sorry and that's why i tried it. I had to write on the assumption no one on here will have seen my AA thread. There was some other things i ended up trying first aswell as this one was going to be a harder to do.
I will definitely post up a schematic here and in AA once i have run some new wiring and done some better tests. I did get one photo which ill put up but it was hard to do as i was holding the luma wire for sync in place on the pcb at the same time.
jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

MarkOZLAD wrote:
jeffez wrote:I got it working. As i suspected it wasn't using the sync signal on the luma pin. I fed luma into the video signal coming from the tuner block and got a picture. I also switched to a 0.1uf on chroma. The difference is huge from how it looked before. I can post more details if anyone is interested.
Nice.

Would love to see more details/some photos.
Bratwurst wrote:Yeah this is a solid thread, please post as many pictures/further elaboration as you'd like.

I have a Zenith 13" I want to see about shooting S-video into since it's RF-only, but schematics are scarce and Zenith liked to march to the beat of their own drum.
Happy to, i wasn't expecting all that much interest since this isn't RGB but i think s-video holds up well and worth it on an rf only set. I'll have a schematic in the next day or so. I still need to figure out audio as well.

The blur in the top left might have just been the camera focus. Was hard to get a good pic as i was holding a wire in place at the same time.
Image
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Re: Sony Trinitron S-Video Mod

Post by MarkOZLAD »

jeffez wrote:Happy to, i wasn't expecting all that much interest since this isn't RGB but i think s-video holds up well and worth it on an rf only set. I'll have a schematic in the next day or so. I still need to figure out audio as well.
I'm interested in all sorts of mods for CRT. I've found modding for S-Vid and Component to be a lot of fun too.

I seem to learn something from everyone I help mod.

Forcing AV and auto switch on mods to allow use for arcade are also interest me.
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MarkOZLAD
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Re: Sony Trinitron S-Video Mod

Post by MarkOZLAD »

I searched my records and found a complete datasheet for the CXA1213AS
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freakaftr8
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Re: Sony Trinitron S-Video Mod

Post by freakaftr8 »

Wow great job! Looks awesome! So I'm assuming that fringe artifacts are non existent now after bypassing the tuner?

Also can you take a picture of your work? Thanks!

I'm thinking this mod should done to my KV-1926RA
jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

[Update - this didn't work when running 480i/576i see further down for updated diagrams]

Finally got time to do some more work and testing.
Here is a schematic. I also added composite with what should be a DPDT twitch. Some of these components are already on the tv pcb but i added them on here to show the whole circuit from the video port to jungle ic. It's not shown but the video signal also may need to be cut from the tuner so it doesn't interfere with sync. See next diagram.

Edit : Diagram outdated. Improved diagrams further down.
https://i.imgur.com/1VH1GJ4.png
Last edited by jeffez on Thu Mar 05, 2020 5:09 am, edited 2 times in total.
jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

[Update - this didn't work when running 480i/576i see further down for updated diagrams]

The underlying schematic is taken from link 1 page 17 on the OP. It's rough but shows what i did. I won't claim this is the best/correct way it's just what i have working.
I'm running my wiring under the pcb so to bypass the rf lines i cut some traces (i know some people aren't into that) but the same thing can be achieved from the top by lifting two resistor legs and one IC pin on the jungle.

Maybe this could be improved if there's a way to put the tv in AV mode? The CXA1213AS jungle chip is used in other TVs which have composite input. Being rf only this tv can't go into AV mode stock but maybe this can be bypassed? This would simplify the mod as you wouldn't have to remove the Chrome and Luma out of the circuit when when running s-video. This may not be an option for really old sets though with jungle chips that were only ever used in rf only tvs.

Edit : Diagram outdated. Improved diagrams further down.
https://i.imgur.com/9aW2Rtp.png
Last edited by jeffez on Thu Mar 05, 2020 5:10 am, edited 3 times in total.
jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

freakaftr8 wrote:Wow great job! Looks awesome! So I'm assuming that fringe artifacts are non existent now after bypassing the tuner?

Also can you take a picture of your work? Thanks!

I'm thinking this mod should done to my KV-1926RA
Thanks. I'm a bit new to all this and i couldn't find what fringe artifacts are but i'll put up some photos comparing rf/composite/s-video.
Right now i just have everything running through a bread board and haven't installed any ports on the tv yet but i can put up photos of that for now if at all useful.
jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

Slight problem i tried using a sega saturn and it's not working properly. Colour is gone and h and v sync is drifting. I wen't back and made sure it still worked with the snes. I then tried with another snes and it worked. I tried with both a model 1 and model 2 saturn and it had the same problem. I can only conclude there is something different between how a snes and sega saturn output s-video.
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

Some comparison photos

Image
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FinalBaton
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Re: Sony Trinitron S-Video Mod

Post by FinalBaton »

Awesome mod, well done OP.

Those sets look just like the North American KV-xxTS20/TS30, which use the same tube as PVM-2030/2530, and most of the same circuit picture enhancement. been considering picking up a KV-27TS30 for a while actually (the TS30 does S-video natively. But modding a TS20 would be cool and would give it a new lease on life)
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jeffez
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

FinalBaton wrote:Awesome mod, well done OP.

Those sets look just like the North American KV-xxTS20/TS30, which use the same tube as PVM-2030/2530, and most of the same circuit picture enhancement. been considering picking up a KV-27TS30 for a while actually (the TS30 does S-video natively. But modding a TS20 would be cool and would give it a new lease on life)
Thanks there's still more work for me to do when i get time. As mentioned testing with a sega saturn (480i?) had problems. I think maybe sync could be injected somewhere better. Also there must be a way to blank out the video coming from the stock rf which would mean no need to cut the C and Y lines.

Those sets you mention must be from a similar family of TVs. Looks like they have a CXA1013S jungle (slightly older?) and basically the same circuitry with the C and Y lines. That's cool to know some older PVMs used the same tube. Such a great screen being restricted with only an antenna input.
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

I finally got some time to get back to this. I found what i think is the best spot to connect luma to provide sync just before the signal splits out to h and v sync input pins on the jungle. 480i now has no sync problems and the snes 240p still works fine. The only issue is luma appears to be too dark when running 480i. If/when i solve this i will revise my diagrams above.

Background should be bright white but is darkened.
Image

This my setup for now. All these wires run out to a breadboard. I found in my case it was easier and safer to just run everything underneath the pcb. Allot of these wires will be removed in the end as some are just for testing different points. There are 5 wires alone just to test each possible spot i could find to inject the sync on luma.
Image
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

I'm still going with this. It's almost there, infact i thought it was solved but in some bright screen situations i still get some hsync misalignment.
The only clue is that if luma is too dark (by lowering the luma 75R termination to around 25R) then the hsync problem goes away.
I need the effect of darkening luma going to sync without affecting the signal going to the luma pin.
I tried using a voltage divider with a potentiometer and connecting sync to that but it only made things worse.

Here's an example of what i mean. The text appears slanted.
Image
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KatKya
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Re: Sony Trinitron S-Video Mod

Post by KatKya »

Currently looking into how to manage an S-Video mod on a 27HFR (google brought me here thanks to the mention of the CXA1013S in one of the posts) but taking a quick glance at what you're doing, a thought came to mind.

Originally I was going to suggest that you just input Y/Luma at the composite input before realizing this is an RF only set you're working on.

While your current approach to Luma injection could prove fruitful, have you considered working backwards toward the tuner, finding where it spits out the baseband composite signal, and then injecting Y there? You'd be able to benefit from the set knowing exactly how to handle what would essentially be a B/W Composite image, and not run into any of the artifacting that would usually result from needing to extract chroma, which you seem to have already worked out how to properly feed in further down the line.

Edit: Looking back through, it appears as though you've already been working towards that. Looking for a moment at the service manual you linked for the "lists mine as a related model", it looks as though it's suggesting the waveform just after Q201 is a nearly standard composite one, just around the 1vp-p would would expect.. Have you attempted to inject there, where it marks with a circled 2?
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

KatKya wrote:Currently looking into how to manage an S-Video mod on a 27HFR (google brought me here thanks to the mention of the CXA1013S in one of the posts) but taking a quick glance at what you're doing, a thought came to mind.

Originally I was going to suggest that you just input Y/Luma at the composite input before realizing this is an RF only set you're working on.

While your current approach to Luma injection could prove fruitful, have you considered working backwards toward the tuner, finding where it spits out the baseband composite signal, and then injecting Y there? You'd be able to benefit from the set knowing exactly how to handle what would essentially be a B/W Composite image, and not run into any of the artifacting that would usually result from needing to extract chroma, which you seem to have already worked out how to properly feed in further down the line.

Edit: Looking back through, it appears as though you've already been working towards that. Looking for a moment at the service manual you linked for the "lists mine as a related model", it looks as though it's suggesting the waveform just after Q201 is a nearly standard composite one, just around the 1vp-p would would expect.. Have you attempted to inject there, where it marks with a circled 2?
Edit : I'm just going to completely edit my last post as it was wrong. I was away and couldn't open the schematics on my phone.

To answer your question yes. Injecting where it is circled 2 is what i am doing. More to the point, the base of Q303. It was the result of allot of trial and error as i couldn't get a clear enough understanding from the datasheets. How did you work out the waveform after Q201 is around to 1vp-p? I've been meaning to do a new diagram of my setup which ill do later today. It's allot simpler than my first solution. For the most part it's working really well with a clean vibrant picture. The slanted text problem shown above has been fixed.
Last edited by jeffez on Wed Feb 26, 2020 12:31 am, edited 3 times in total.
awbacon
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Re: Sony Trinitron S-Video Mod

Post by awbacon »

I still want to get a Wega and mod it for RGB. I love my 14" PVM's but I want to get something more in a 20 to 27" model without spending 1000's on it
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KatKya
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Re: Sony Trinitron S-Video Mod

Post by KatKya »

jeffez wrote: To answer your question yes. Injecting where it is circled 2 is what i am doing. More to the point, the base of Q303. It was the result of allot of trial and error as i couldn't get a clear enough understanding from the datasheets. How did you work out the waveform after Q201 is around to 1vp-p? I've been meaning to do a new diagram of my setup which ill do later today. It's allot simpler than my first solution. For the most part it's working really well with a clean vibrant picture. The slanted text problem shown above has been fixed.
The first linked service manual, on page 17 which shows all of the A-Board, also has waveforms for different test points on the board. Point 2 shows what looks to be a standard composite waveform (doesn't show color burst, but likely just not caring to go for 100% accuracy for the diagram) and is notated as being "0.9Vp-p".


Not that it's directly related to your mod, but since the previous message, I went though with testing out the s-video "mod" I previously said I was researching on my KV-27HFR. In case google brings someone here: Lift C357 on the side facing the comb filter (towards the rear of the TV) and feed chroma directly through said cap. Despite the schematic seemingly suggesting a considerably hotter chroma signal, it'll accept it straight from an external source no problem. Alternatively, you can cut it out of circuit and provide your own coupling capacitor. Feed Luma to the composite input of choice and you're done. This will leave any composite signal fed as black and white unless you install a switch to go back and forth between the comb filter's chroma, and your injected chroma.

CXA1013 27HFR S-Video Mod
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Kabal2X
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Re: Sony Trinitron S-Video Mod

Post by Kabal2X »

Excellent thread, might have to try this with my KV-21R20, with jungle chip CXA1870S, which has Y and C inputs avaliable and not used, as this is a composite input only TV. Thanks for sharing!
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

KatKya wrote: The first linked service manual, on page 17 which shows all of the A-Board, also has waveforms for different test points on the board. Point 2 shows what looks to be a standard composite waveform (doesn't show color burst, but likely just not caring to go for 100% accuracy for the diagram) and is notated as being "0.9Vp-p".
Thanks, how did i miss that! For the sake of it i tried a voltage divider to get 0.9Vp-p before injecting it but no difference. I think the minor sync issues i am getting might just be my tv. I will see if i get improvement when i clean up the wiring and ground the shielded cable i am using.
Kabal2X wrote:Excellent thread, might have to try this with my KV-21R20, with jungle chip CXA1870S, which has Y and C inputs avaliable and not used, as this is a composite input only TV. Thanks for sharing!
No problem, i was suppose to do a new diagram but i have not got to it just yet. It should be very easy to inject sync with yours if it already has composite.
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Re: Sony Trinitron S-Video Mod

Post by jeffez »

Here are the new revised diagrams. I have tried allot of different variations and this is the best and simplest working setup i have found so far. I will be adding in audio next. Hopefully this will help bring back some more rf only sets!

There's both a schematic and a physical layout diagram.

Image

Image

Very clean vibrant picture from a sega saturns s-video. The blur and other imperfections only showed as a result of my camera.
Image

Image
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